Arrangement for electrical connections



Dec. 15, 1964 H. E. TROMHOLT 3,161,808

ARRANGEMENT FOR ELECTRICAL CONNECTIONS Filed July 24, 1961 FIGJ FIG. 2

INVENTOR.

HANS E. TROMHOLT ATTORNEY United States Patent 3,161,808 ARRANGEMENT FOR ELECTRICAL CONNECTIONS Hans E. Tromholt, Monrovia, Cali'rl, assignor to Leach Corporation, Compton, Calif. Filed July 24, 1961, Ser. No. 126,016 7 Claims. (Cl. 317-158) This invention pertains to an arrangement for connecting electrical components and is particularly useful in the construction of relays.

Relay coils commonly are made up of a large number of turns of fine copper wire wound around a spool. There may be, for example, an excess of five thousand turns of forty-five gage wire in a typical relay design. It is nec essary, of course, to connect the ends of the coil into the electrical circuit of the relay in order that current may be passed through turns of the coil. The fine copper wire is much too fragile to be utilized directly as the connecting medium. Therefore, it has been the usual practice to supply a lead wire at either end of the wire of the coil, the lead wire being of heavier gage and extending from the coil to the pins of the relay header. Normally this wire is soldered both tothe ends of the coil wire and to the connector post with which it is associated.

This results in distinct disadvantages. At elevated temperatures the soldered joints may evolve gases damaging to the relay unit. This is particularly true for hermetically sealed relays utilized under the exacting conditions required in high performance aircraft or space vehicles. In such installations, gases from soldered joints cannot be tolerated.

In an effort to alleviate this difliculty, it has been the frequent practice to bake the assembly for a period of time in the hope of driving off the soldering gases prior to the actual use of the relay. Despite prolonged exposure to elevated temperatures, however, there is no complete assurance that all of the gases have been driven oil at the time the relay is put into use. Therefore, conventional procedures have not resulted in units of needed reliability. Furthermore, this procedure has the obvious disadvantage of additional cost and consumption of time necessitated by the baking process.

According to the provisions of this invention an arrangement is provided whereby fine wire may be connected in a circuit without the use of any soldered joints. This is accomplished by utilizing a lead wire assembly in the form of a multiplicity of strands of a weldable wire material. The thin relay wire is twisted into the strands of the lead wire cable at one end, while the opposite end of the lead wire is used to connect the coil to the circuit. This permits the end of the lead wire to be welded to the pins of the relay resulting in a unit in which no soldered joints are present. The weldable multiple strand lead wire provides an adequate support so that the fine copper wire of the relay coil will not be broken, while at the same time the absence of soldering assures that no foreign matter is present in the completed unit. While particularly adapted for use in relays, the teachings of this invention may be used to advantage in other electrical devices as we 1.

Therefore, it is an object of this invention to provide a solderless connection of electrical components.

Another object of this invention is to provide electrical leads of weldability and appropriate mechanical strength.

A further object of this invention is to provide a relay having no soldered joints.

Yet another object of this invention is to reduce the cost and construction time of relays.

These and other objects will become apparent from the 3,161,808 Patented Dec. 15, 1964 following detailed description taken in connection with the accompanying drawing in which:

FIG. 1 is a side elevational view, partially broken away, of a relay constructed in accordance with the teachings of this invention,

FIG. 2 is an enlarged fragmentary elevational view showing the attachment of the coil wire to the multiple strand lead wire, and

FIG. 3 is a sectional view taken along line 33 of FIG. 2 illustrating the coil wire as Wound together with the lead wire.

A typical relay unit may be seen in FIG. 1 where a sheet metal can 1 attaches to the base plate 2 of a header assembly. The header supports coil 3 within the relay from which extends lead wires 4 and 5 that connect at their outer ends to pins 6 and 7. These pins include lower portions 8 and 9 projecting downwardly from the base flange 2 of the header to the exterior of the relay, providing a means for connection to appropriate electrical circuits. Thus wires may be joined to the bottom ends 8 and 9 of the pins 6 and 7 permitting current to flow through the coil to actuate the relay armature 10.

For many present day installations the interior of the relay can 1 will be sealed from the exterior environment, and the relay can will be filled with an inert gas such as nitrogen.

The relay coil 3 is made up of a multiplicity of turns of fine copper wire 11 wound around a suitable bobbin 12. The lead wires 4 and 5 extend outwardly from the central portion of the coil through a wrapping 13 of Teflon or other suitable material.

According to the provisions of this invention each of the lead wires is made up of a number of strands 14 of a weldable wire material. The number of strands and their gage may vary as well as the material selected. Six strands of stainless steel wires may be used satisfactorily. These strands may be woven together so that even though each strand is of small diameter, in the aggregate they provide a wire assembly of considerable mechanical strength and electrical conductivity.

The end of the copper wire 11 of the relay coil is received within the strands 14 of the lead wire and is woven therein (see FIGS. 2 and 3). As illustrated, the coil wire 11 is wound around the end of the lead wire cable at the end where the cable joins the coil wire. After a few turns around the exterior of the cable end, the coil wire is woven into the cable as part of the assembly of strands. Thus, a length of the end of the coil wire, by being twisted together with the strands of the lead wire, become mechanically fastened to the lead wire. Additionally, it is electrically connected to the lead wire in view of the large surface area contacted where the strands of the lead wire are twisted around the coil wire. The distance the coil wire extends with the cable is not critical, so long as an adequate mechanical support is provided and good electrical contact is made. The fine coil wire is anchored within the wrapping 13, and there is no portion of this fragile element that is unsupported. The outer end of the lead wire may be wound around the pin as illustrated in FIG. 1 and welded to the pin at this point. The result is an electrical connection of the coil to the remainder of the circuit without the use of any solder whatsoever. The fine relay wire is supported mechanically by the stronger multiple strand lead Wire, while a positive electrical connection is effected by the twisting of the lead wire around the wire of the relay coil.

Therefore, according to the provisions of invention it is a simple matter to merely twist the ends of the lead wire about the ends of the wire of the coil after which the lead wires are welded to the contact post of the relay. Not only is the construction time for the relay 3 reduced, but a completely uncontaminated relay results. The connection to the relay coil wires is particularly strong and reliable, yet no possibility exists for gases to be present within the relay as a result of the joining of the relay wire.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

I claim:

1. In combination with a relatively fine wire, an arrangement for connecting said relatively fine Wire into an electrical circuit comprising a multiple strand cable of individual Wires, one end of said cable being twisted together with an end of said relatively fine wire to form a unitary woven connection, the opposite end of said multiple strand cable being attachable in an electrical circuit.

2. In combination with a relatively fragile electrically conductive wire and an adjacent electrically conductive wire and an adjacent electrically conductive element, an arrangement for connecting said wire to said conductive element comprising a multiple strand cable of weldable wires, one end of said cable being wound together with said realtively fine wire, the opposite end of said cable being welded to said electrically conductive member.

3. A component for an electric circuit comprising a wire of relatively small diameter, a cable of a plurality of strands of a weldable material receiving one end of said wire and wound together with the same, the opposite end of said cable being weldable to an electrically conductive element.

4. A relay coil means comprising relatively fine wire wound into a plurality of turns, and a duality of electrical lead Wires connected one to either end of said relatively fine wire, each of said lead Wires comprising a cable of a plurality of strands of a weldable material receiving an end of said relatively fine wire and being twisted about the same.

5. A relay coil means comprising a plurality of turns of relatively fine wire, a cable of a plurality of strands of weldable material receiving either end of said relatively fine wire and twisted together with the same, and a duality of connector pins, the opposite ends of said cables being welded to said connector pins.

6. A relay comprising a sealed housing, coil means in said housing, an armature operable by said coil means, a duality of lead Wires, and a duality of electrical contact posts, said coil means including a plurality of turns of relatively fine wire, said lead wires comprising woven cables of a plurality of strands of weldable material, one end of each of said cables being welded to one of said contact posts, the opposite end of each of said cables being wound together with an end of said relatively fine wire to form a mechanical connection with said relatively fine wire with a relatively large surface contact area between said cable and said relatively fine wire.

7. A device as recited in claim 6 in which said relatively fine wire is copper and said strands of said lead wires are stainless steel.

References Cited in the file of this patent UNITED STATES PATENTS 2,725,440 Kamm Nov. 29, 1955 2,794,176 Barnes May 28, 1957 3,020,333 Bangert et al Feb. 6, 1962 

1. IN COMBINATION WITH A RELATIVELY FINE WIRE, AN ARRANGEMENT FOR CONNECTING SAID RELATIVELY FINE WIRE INTO AN ELECTRICAL CIRCUIT COMPRISING A MULTIPLE STRAND CABLE OF INDIVIDUAL WIRES, ONE END OF SAID CABLE BEING TWISTED TOGETHER WITH AN END OF SAID RELATIVELY FINE WIRE TO FORM A UNITARY WOVEN CONNECTION, THE OPPOSITE END OF SAID MULTIPLE STRAND CABLE BEING ATTACHABLE IN AN ELECTRICAL CIRCUIT. 